在 .Net Core 的 ServiceStack.OrmLite 使用 SqlGeography

Question

我尝试将 SqlGeography 添加到我的模型中，当我调用 create table 时出现奇怪的错误。

首先我添加这个包：Microsoft.SqlServer.Types

然后我创建我的模型，如下例所示：

public class Locations 
{
   public int Id { get; set; }
   public string Name { get; set; }
   public SqlGeography Location { get; set; }
}

然后调用CreateTableIfNotExists创建table

private void CheckDB(IDbConnectionFactory dbConnectionFactory)
{
    using (var db = dbConnectionFactory.Open())
    {
        db.CreateTableIfNotExists<Models.Entities.DbIpEntity>();
    }
}

最后我得到了这个错误：

System.TypeLoadException HResult=0x80131522 Message=Could not load type 'Microsoft.SqlServer.Server.IBinarySerialize' from assembly 'System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Source=System.Private.CoreLib
StackTrace: at System.Signature.GetSignature(Void* pCorSig, Int32 cCorSig, RuntimeFieldHandleInternal fieldHandle, IRuntimeMethodInfo methodHandle, RuntimeType declaringType) at System.Reflection.RuntimeMethodInfo.FetchNonReturnParameters() at System.Reflection.RuntimeMethodInfo.GetParametersNoCopy() at System.Reflection.RuntimePropertyInfo.GetIndexParametersNoCopy() at System.Reflection.RuntimePropertyInfo.GetIndexParameters() at ServiceStack.OrmLite.OrmLiteConfigExtensions.GetModelDefinition(Type modelType) at ServiceStack.OrmLite.OrmLiteWriteCommandExtensions.CreateTable(IDbCommand dbCmd, Boolean overwrite, Type modelType) at ServiceStack.OrmLite.OrmLiteExecFilter.Exec[T](IDbConnection dbConn, Func`2 filter) at ServiceStack.OrmLite.OrmLiteSchemaApi.DropAndCreateTable[T](IDbConnection dbConn) at GeoApi.AppHost.CheckDB(IDbConnectionFactory dbConnectionFactory) in E:\Projects\Geo\AppHost.cs:line 48 at GeoApi.AppHost.Configure(Container container) in E:\Projects\Geo\AppHost.cs:line 40 at ServiceStack.ServiceStackHost.Init() at ServiceStack.NetCoreAppHostExtensions.UseServiceStack(IApplicationBuilder app, AppHostBase appHost) at GeoApi.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env) in E:\Projects\Geo\Startup.cs:line 49

在这个错误中，我意识到它正在寻找 .Net Framework 程序集（System.Data, Version=4.0.0.0）而不是 .Net Core

Answer 1

定义 SqlGeography 的 ServiceStack.OrmLite.SqlServer.Converters and Microsoft.SqlServer.Types 仅分别适用于 .NET v4.5 和 .NET v4.0，因此至少需要 .NET v4.5 到运行并且不能在 .NET Core 中使用。

Answer 2

.net core 2.2 现在支持使用 GeoSpatial 数据 - https://docs.microsoft.com/en-us/ef/core/modeling/spatial

我能够根据 the SqlServerGeographyTypeConverter here.

拼凑出自己的 OrmLiteConverter

public class SqlServerIPointTypeConverter : OrmLiteConverter
{
    public override string ColumnDefinition => "geography";
    public override DbType DbType => DbType.Object;

    public override string ToQuotedString(Type fieldType, object value)
    {
        if (fieldType != typeof(IPoint)) return base.ToQuotedString(fieldType, value);

        string str = null;
        if (value != null)
        {
            var geo = (IPoint) value;
            str = geo.ToString();
        }

        str = (str == null) ? "null" : $"'{str}'";
        return $"CAST({str} AS {ColumnDefinition})";
    }

    public override void InitDbParam(IDbDataParameter p, Type fieldType)
    {
        if (fieldType == typeof(IPoint))
        {
            var sqlParam = (SqlParameter)p;
            sqlParam.IsNullable = fieldType.IsNullableType();
            sqlParam.SqlDbType = SqlDbType.Udt;
            sqlParam.UdtTypeName = ColumnDefinition;
        }

        base.InitDbParam(p, fieldType);
    }

    public override object FromDbValue(Type fieldType, object value)
    {
        switch (value)
        {
            case null:
            case DBNull _:
                return new Point(0, 0);
            case IPoint point:
                return point;
            case string _:
                return Parse(value.ToString());
            default:
                return base.FromDbValue(fieldType, value);
        }
    }

    public override object ToDbValue(Type fieldType, object value)
    {
        switch (value)
        {
            case null:
            case DBNull _:
                return new Point(0, 0);
            case IPoint _:
                return value;
            case string str:
                return Parse(str);
            default:
                return base.ToDbValue(fieldType, value);
        }
    }

    private static Point Parse(string rawPoint)
    {
        var split = rawPoint.Replace("POINT (", string.Empty)
            .Replace(")", string.Empty)
            .Trim()
            .Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries);

        var longitude = Convert.ToDouble(split[0]);
        var latitude = Convert.ToDouble(split[1]);

        return new Point(longitude, latitude);
    }
}

然后在您的 AppHost 文件中：

SqlServerDialect.Provider.RegisterConverter<Point>(new SqlServerIPointTypeConverter());

只要您使用的是 dotnet core 2.2，并且引用了以下 Nuget 包，它就应该可以工作：

在 .Net Core 的 ServiceStack.OrmLite 使用 SqlGeography

Use SqlGeography at ServiceStack.OrmLite in .Net Core

c#

servicestack

ormlite-servicestack

.net-core